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Добірка наукової літератури з теми "COP IMPROVEMENT"

Автор: Grafiati

Опубліковано: 10 березня 2023

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Статті в журналах з теми "COP IMPROVEMENT"

Liu, Ying Fu, and Guang Ya Jin. "Vortex Tube Expansion Two-Stage Transcritical CO₂ Refrigeration Cycle." Advanced Materials Research 516-517 (May 2012): 1219–23. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1219.

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Use of vortex tube as an expansion device in transcritical CO2 cycle could reduce the throttle loss and improve the coefficient of performance. In this paper, a vortex tube expansion two-stage transcritical CO2 refrigeration cycle(VTTC) is established and compared to that of the two-stage transcritical CO2 refrigeration cycle with throttle valve(TVTC). Thermodynamic analysis results indicate that there is also an optimum heat rejection pressure for the vortex tube cycle, and the COP improvement is 2.4%~16.3% at given conditions. Decrease in evaporation temperature or increase in gas-cooler outlet temperature decrease the COP, but the COP improvement will increase. The effect of cold mass fraction on the COP is negligible, but the COP improvement will increase fast with the increase of cold mass fraction.

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Xie, Ying Bai, Kui Kui Cui, Zhi Chao Wang, and Jian Lin Liu. "CO₂ Trans-Critical Two Stage Compression Refrigeration Cycle with Vortex Tube." Applied Mechanics and Materials 52-54 (March 2011): 255–60. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.255.

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Анотація:

The paper analyses CO2 trans-critical two stage compression refrigeration cycle with vortex tube expansion by thermodynamics method. And compare with CO2 trans-critical two stage compression refrigeration cycle with expansion value. The results show that in the calculated conditions of the paper, the performance of the cycle with vortex tube improves 2.4%~16.3% than the cycle with expansion value. The optimal discharge pressure maximizing COP of the cycle with vortex tube exists. With lower evaporating temperature or higher gas cooler exit temperature, COP of system decreases and COP improvement increases. The effect of cold fluid mass fraction on COP is not significant, but COP improvement increases more quickly with cold gas mass fraction increasing.

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Liu, Yefeng, Ying Sun, and Danping Tang. "Analysis of a CO2 Transcritical Refrigeration Cycle with a Vortex Tube Expansion." Sustainability 11, no. 7 (April 4, 2019): 2021. http://dx.doi.org/10.3390/su11072021.

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Анотація:

A carbon dioxide (CO2) refrigeration system in a transcritical cycle requires modifications to improve the coefficient of performance (COP) for energy saving. This modification has become more important with the system’s more and more widely used applications in heat pump water heaters, automotive air conditioning, and space heating. In this paper, a single vortex tube is proposed to replace the expansion valve of a traditional CO2 transcritical refrigeration system to reduce irreversible loss and improve the COP. The principle of the proposed system is introduced and analyzed: Its mathematical model was developed to simulate and compare the system performance to the traditional system. The results showed that the proposed system could save energy, and the vortex tube inlet temperature and discharge pressure had significant impacts on COP improvement. When the vortex tube inlet temperature was 45 °C, and the discharge pressure was 9 MPa, the COP increased 33.7%. When the isentropic efficiency or cold mass fraction of the vortex tube increased, the COP increased about 10%. When the evaporation temperature or the cooling water inlet temperature of the desuperheater decreased, the COP also could increase about 10%. The optimal discharge pressure correlation of the proposed system was established, and its influences on COP improvement are discussed.

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ITOU, Hiroshi, Hiroyuki NANBU, and Hiromi MORI. "COP improvement for encapsulated ice storage system." Proceedings of the Symposium on Environmental Engineering 2004.14 (2004): 340–43. http://dx.doi.org/10.1299/jsmeenv.2004.14.340.

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Sarkar, Jahar. "Performance improvement of double-tube gas cooler in CO2 refrigeration system using nanofluids." Thermal Science 19, no. 1 (2015): 109–18. http://dx.doi.org/10.2298/tsci120702121s.

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Анотація:

The theoretical analyses of the double-tube gas cooler in transcritical carbon dioxide refrigeration cycle have been performed to study the performance improvement of gas cooler as well as CO2 cycle using Al2O3, TiO2, CuO and Cu nanofluids as coolants. Effects of various operating parameters (nanofluid inlet temperature and mass flow rate, CO2 pressure and particle volume fraction) are studied as well. Use of nanofluid as coolant in double-tube gas cooler of CO2 cycle improves the gas cooler effectiveness, cooling capacity and COP without penalty of pumping power. The CO2 cycle yields best performance using Al2O3-H2O as a coolant in double-tube gas cooler followed by TiO2-H2O, CuO-H2O and Cu-H2O. The maximum cooling COP improvement of transcritical CO2 cycle for Al2O3-H2O is 25.4%, whereas that for TiO2-H2O is 23.8%, for CuO-H2O is 20.2% and for Cu-H2O is 16.2% for the given ranges of study. Study shows that the nanofluid may effectively use as coolant in double-tube gas cooler to improve the performance of transcritical CO2 refrigeration cycle.

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Garimella, S. "Absorption Heat Pump Performance Improvement Through Ground Coupling." Journal of Energy Resources Technology 119, no. 4 (December 1, 1997): 242–49. http://dx.doi.org/10.1115/1.2794997.

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The present study investigates the improvement in the performance of an absorption heat pump for residential space-conditioning due to the use of the ground as the heat source in the heating mode and the heat sink in the cooling mode. A baseline air-coupled single-effect ammonia-water heat pump is first designed to deliver 10.55 kW (36,000 Btu/h) of cooling load at the ARI rating conditions. Particular attention is paid to incorporating many realistic details of an operating system such as fuel combustion efficiencies of the burner, nonequilibrium conditions, and moist air processes in the air-coupled heat exchangers. A range of parametric studies is also conducted to investigate the variation in performance of this system with ambient conditions in the heating and cooling modes. The same system is then analyzed in a ground-coupled configuration. The instantaneous COP for the ground-coupled system is compared with the COP of the air-coupled system as a function of the time of the year and the corresponding variations in ambient and ground temperatures using 30-yr average climate data for various locations from the National Weather Service. Improvements in COP of up to 20 percent over the air-coupled system values (cooling mode COP of 0.495 at 35°C (95°F) and heating mode COP of 1.20 at 8.33°C (47°F)) are demonstrated in diverse geographic locations with widely varying heating and cooling loads. These improvements indicate that an efficient ground-coupled heat pump could be developed for residential space-conditioning applications using simple thermodynamic cycles and existing technology for the heat and mass exchange components.

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Çoban, Fahriye, Beliz Belgen Kaygısız, and Ferda Selcuk. "Effect of clinical Pilates training on balance and postural control in patients with Parkinson’s disease: a randomized controlled trial." Journal of Comparative Effectiveness Research 10, no. 18 (December 2021): 1373–83. http://dx.doi.org/10.2217/cer-2021-0091.

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Анотація:

Background: Clinical pilates exercises have been shown to improve balance. Our study aims to compare effects of clinical Pilates and conventional physiotherapy exercises on balance and postural control in Parkinson’s disease patients. Materials & methods: Forty patients were randomly assigned into either clinical Pilates (CLP) or conventional physiotherapy (COP) group. Exercises were performed twice a week for 8 weeks. Balance, lower-extremity strength, fall risk and functional mobility were assessed at the beginning and end of the exercise period. Results: All measurements indicated significant increase in two groups (p < 0.05). Compared with the COP group, the CLP group showed significant improvement in dynamic balance values (p < 0.05). Conclusion: CLP was as effective as COP, with better dynamic balance results, and could be used in rehabilitation for patients with Parkinson’s disease. Clinical trial registration number: NCT04063605 .

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Mahata, G., and S. Sardar. "Evaluation of elite sugarcane clones/varieties against red rot disease (Colletotrichum falcatum) and their suitability in crop improvement programme." Agricultural Science and Technology 14, no. 1 (March 2022): 28–33. http://dx.doi.org/10.15547/ast.2022.01.004.

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Abstract. To manage red rot disease in sugarcane, several methods like use of bio-control agents, hot water and hot air treatment of setts, chemical fungicides, various cultural practices like use of disease free setts, rouging, crop rotation, irrigation management, avoiding rationing, etc. are practised. But none of the practices are able to control the disease. The most viable strategy is to manage through host plant resistance. Thus, a field experiment was conducted for two consecutive years during 2019 and 2020 at the Research Farm of Sugarcane Research Station, Bethuadahari (West Bengal), India to evaluate some elite sugarcane clones/varieties against red rot disease. The elite clones/varieties were laid out in Completely Randomized Block Design with a plot size of 2R x 6m x 0.90m with 2 replications and two red rot pathotypes Cf 07 and Cf 08 were used for artificial inoculation in plug and nodal method. The experiment revealed that the sugarcane clones CoP 16436, CoP 16437, CoP 16438, CoLk 16466, CoLk 16467, CoLk 16468, CoSe 16451, CoP 16439, CoP 16440, BO 156, CoLk 16469, CoLk 16470, CoLk 16471, CoSe 16452, CoSe 16453, CoSe 16454, CoP 17436, CoP 17437, CoP 17438, CoP 17440, CoP 17441, CoSe 17451, CoSe 16455, CoSe 16456, CoP 17444, CoP 17446 and CoSe 17452 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method to both pathotypes and can be used for further evaluation in subsequent varietal developmental as well as breeding programme. The popular sugarcane varieties, namely CoLk 94184, CoSe 01421, BO 91, CoP 9301 and CoP 06436 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method and can be continued for commercial cultivation as well as red rot breeding programme. As the existing popular variety CoSe 95422 was found moderately susceptible (MS) in plug method and susceptible (S) in nodal method to Cf 07 and Cf 08 red rot pathotypes, thus the variety must be discarded from commercial cultivation with immediate effect.

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Chorowski, Maciej, Piotr Pyrka, Zbigniew Rogala, and Piotr Czupryński. "Experimental Study of Performance Improvement of 3-Bed and 2-Evaporator Adsorption Chiller by Control Optimization." Energies 12, no. 20 (October 17, 2019): 3943. http://dx.doi.org/10.3390/en12203943.

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The main challenge facing adsorption cooling technology is low Coefficient of Performance (COP), which becomes a key factor of the commercialization of this technology. This paper presents the results of modifications, aiming to increase COP, applied to the control software of a prototype three-bed two-evaporator adsorption chiller. Changes were mainly related to the sequence of the switching valves and had no influence on the hardware of the chiller. The sequence changes enabled the introduction of heat recovery and mass regeneration. Moreover, the precooling process was improved. The applied modifications not only resulted in significant improvement of the chiller’s COP, but also improved the cooperation adsorption unit heating source, which is of great importance in case of district heating supply. The improvement was also observed concerning such operational aspects as noise and vibrations. In the authors’ opinion, the presented modifications can be introduced to most exploited adsorption chillers and could potentially lead to similar improvements in performance.

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Liu, Xi, Yueling Li, Kunyu Zhuang, Ruansong Fu, Shi Lin, and Xuelai Li. "Performance Study and Efficiency Improvement of Ice Slurry Production by Scraped-Surface Method." Applied Sciences 9, no. 1 (December 26, 2018): 74. http://dx.doi.org/10.3390/app9010074.

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In this study, the performance of ice slurry production by scraped-surface method was experimentally investigated. Temperature change characteristics, ice packing fraction (IPF) of ice slurry, power consumption of scraping system and coefficient of performance (COP) were measured by varying the concentration of sodium chloride solution, scraping speed, and solution flow rate. The effect of nanosilica on efficiency of ice slurry production was also studied. The results showed that scraping power consumption accounted for only a small proportion (about 5%) of the total power consumption of the system. An increase in the concentration of sodium chloride caused a decrease in the IPF and a decrease in the COP of the system. With the solution flow rate at 1.3 m3/h and scraping speed at 13 rpm, the maximum COP (2.43) was obtained. Furthermore, the addition of nanosilica had a significant effect on improving the system COP.

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Більше джерел

Дисертації з теми "COP IMPROVEMENT"

Motamed, Fath Puria. "Construction of a Copper Bioreporter Screening, characterization and genetic improvement of copper-sensitive bacteria." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19682.

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In the nature, lots of organism apply different kinds of lights such as flourscence or luminoscence for some purposes such as defence or hunting. Firefly luciferase and Bacterial luciferase are the most famous ones which have been used to design Biosensors or Bioreporters in recent decades. Their applications are so extensive from detecting pollutions in the environment to medical and treatment usages. To design Copper Bioreporter, copper resistance promoter from COP operon which plays an important role in Pseudomonas syringae and pGL3 plasmid which has luciferase gene were utilized. To achieve that target, sequences of promoter were synthesized and inserted to pCR2.1 vector, then suitable primers with considering restriction sites were designed to get high concentration of DNA. After digestion of pGL3 and interested gene by Nhe I and Sac I enzymes, ligation was performed, and then recombinat plasmids were transferred to E. coli BL-21 as a host cell. Finallay, luciferase assay of designed bioreporter was performed by Luminometer in presence of different concentration of CuSO4. The result was maginificant that confirmed design of Copper Bioreporter.

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Summerbell, Daniel Leo. "Environmental performance improvement in the cement industry." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275450.

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This research investigates ways to reduce the carbon dioxide emissions from the cement industry. Cement is one of the largest sources of man-made greenhouse gases, contributing ~5% of the global total. 40% of emissions from cement come from the fuel used in the process, while the electricity used contributes a further 5%. The focus of the research is to find operational changes that can reduce emissions without the need for large capital investment. Three cement plants in the UK were investigated using four different mathematical models based on real data from the plants. A new metric for assessing the environmental impact of the fuel mix of a plant was proposed, and evidence indicates that it may be a better predictor of environmental performance than the metrics currently used in industry. The research found that consistently improving this fuel metric to best-observed levels, as well as reducing the excess air ratio to industry-standard levels had the potential to reduce fuel consumption by up to 7%, and fuel derived CO2 emissions by up to 12%. Increasing use of biomass to best-observed levels had the potential to reduce the net fuel derived CO2 emissions by up to 20%. Comparing the proposed improvements to the historic range of plant performance showed that this level of performance is within the normal operating range of the plants. A reduction of 2-4% in electricity costs and electricity derived emissions was also possible from operational changes. These savings would reduce operating costs as well as emissions, and require little to no capital investment, meaning they could be implemented directly. If successfully implemented in the near future the total savings by 2050 would be on a similar scale to those expected from much more expensive technology changes, such as upgrading to new cement plants, or installing carbon capture and storage technology.

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Widenbrant, Elizabeth M. "Novel rearrangement of a streptomyces coelicolor linear chromosome in strain improvement studies /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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Perry, Harriet Harris. "Partnering districts and schools for improvement a study in educational sociology /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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Rosenthal, Blair Dana. "Improving elementary-age children's writing fluency a comparison of improvement based on performance feedback frequency /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2006. http://proquest.umi.com/login?COPT=REJTPTU0NWQmSU5UPTAmVkVSPTI=&clientId=3739.

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Reddick, J. Christopher. "Energy improvements in the post-combustion CO2 capture process by means of ejectors." Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10136.

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Анотація:

Le but principal de ce projet doctoral est de déterminer le potentiel d'amélioration de l'efficacité énergétique du système de captage de carbone dans les stations thermiques de production d'électricité, par l'intégration optimale des éjecteurs monophasiques. Il s'agit du système de captage postcombustion du dioxyde de carbone (CO2) par absorption/désorption utilisant la monoéthanolamine (MEA). Les éjecteurs intégrés utilisent des rejets thermiques de 100 °C qu'on retrouve dans les stations thermiques de production d'électricité. La revalorisation de ces rejets permet la substitution partielle de vapeur de turbine à coût élevé, qui serait autrement prise de la centrale thermique. Le deuxième objectif de la thèse est d'évaluer expérimentalement la performance d'un éjecteur à vapeur où le fluide secondaire de l'éjecteur est un mélange de vapeur d'eau et d'un gaz non-condensable, dans le cas présent, le CO2. Deux tuyères d'éjecteur à vapeur, d'un diamètre de 4.60 mm et 4.23 mm, ont été évaluées sur une plage de niveaux de CO2 dans le fluide secondaire, jusqu'à environ 40% en masse. La pression primaire était maintenue à 450 kPa avec une surchauffe à 10 °C et la pression secondaire était de 70 kPa. On a constaté que la pression critique ne changeait pas à mesure que la fraction massique de CO2 dans le fluide secondaire augmentait. Cependant, le rapport d'entraînement a augmenté de façon linéaire sur la plage expérimentale. Une amélioration de 23% du rapport d'entraînement par rapport à la vapeur pure a été observée lorsque le fluide secondaire contient 42% de CO2 par masse. Ce comportement contraste nettement avec le comportement observé expérimentalement d'un éjecteur à vapeur pure, où une augmentation du rapport d'entraînement se produit au détriment d'une diminution de la pression critique. Trois articles détaillés ont été publiés sur divers scénarios d'intégration d'un éjecteur à vapeur dans un procédé de captage d'absorption/désorption. Le solvant de référence était de 20% en masse de monoéthanolamine (MEA). Trois configurations principales ont été étudiées, selon le choix du fluide utilisé pour produire la vapeur secondaire : éjecteur sur condensat, éjecteur sur pauvre ou éjecteur sur riche. La première publication de revue scientifique a porté sur le procédé de désorption et a présenté une méthode de raccourci basée sur les propriétés du mélange CO2-MEA-H2O à l'équilibre. Les simulations ont révélé des réductions dans la quantité requise d'énergie de haute qualité, de 10 à 25%. Un simulateur de procédé commercial, Aspen Plus, a été utilisé pour les deux autres publications. Dans la deuxième publication de revue scientifique, le module cinétique rate-based a été utilisé, au lieu du module d'équilibre, pour la modélisation de l'absorbeur et du désorbeur, permettant des évaluations énergétiques plus près des valeurs qu'on retrouve dans la littérature courante. Une étude a été réalisée pour comparer un scénario de préchauffage de la vapeur primaire par des rejets thermiques externes avec un scénario d'intégration de la chaleur interne. Cette deuxième publication a montré des économies d'énergie de haute qualité, de 10 à 14%, les scénarios avantageux ayant été «éjecteur sur condensat» et «éjecteur sur pauvre».
Abstract : The main goal of the doctoral project is to determine to what extent the optimal integration of single-phase ejectors might reduce the large amount of energy required to capture carbon dioxide from electric power generation facilities. More specifically, the objective is to determine if ejectors can be advantageously integrated into a post-combustion absorption/desorption carbon dioxide (CO2) capture process using monoethanolamine (MEA). The integrated ejectors will use waste heat of 100 °C from the electric power plant. The upgraded waste heat can partially replace valuable turbine steam that would otherwise be taken from the power plant. The second objective of the thesis is to experimentally evaluate the performance of a steam ejector where the ejector secondary fluid is a mixture of steam and a non-condensable gas, in this case CO2. Two steam ejector nozzles, of 4.60 mm and 4.23 mm diameter, were evaluated over a range of secondary fluid CO2 levels, up to 42% by mass. The primary pressure was maintained at 450 kPa with 10 °C superheat and the secondary pressure was 70 kPa. It was found that the critical exit pressure did not change as the mass fraction of CO2 in the secondary fluid increased. The entrainment ratio, however, increased approximately linearly over the experimental range. An improvement of 23% in the entrainment ratio, as compared with pure steam, was found when the secondary fluid contains 42% CO2 by mass. This behaviour is in sharp contrast to the experimentally observed behaviour of a pure steam ejector, where an increase in entrainment ratio comes at the expense of a decrease in the ejector exit critical pressure. Three published papers investigated various scenarios for the integration of a steam injector into an absorption/desorption post-combustion capture process. The reference solvent was 20% weight monoethanolamine (MEA). Three principal configurations were studied, according to the choice for the liquid flow used to produce the ejector secondary steam: ejector on condensate, ejector on lean or ejector on rich. The first journal publication focused on the desorption process and presented a shortcut method based on CO2-MEA-H2O equilibrium vapour liquid data. The simulations revealed reductions in the required amount of valuable energy from 10 to 25%. A commercial process simulator, Aspen Plus, was used for two other publications. In the second journal publication, the kinetic rate-based module was employed to model the absorber and desorber, providing energy evaluations closer to values in the open literature. A study was included comparing preheating the primary steam with waste heat or by heat integration. The rate-based simulation found valuable energy savings of 10 to 14%, with the "ejector on condensate" and "ejector on lean" again being the advantageous scenarios.

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Chaloupecký, Martin. "Testing process improvement a implementace vylepšení." Master's thesis, Vysoká škola ekonomická v Praze, 2013. http://www.nusl.cz/ntk/nusl-165077.

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This thesis deals with the testing process improvement and the implementation of specific improvement. Its objective is to describe the methodology TPI NEXT, define possible approaches to synchronization tools HP Quality Center and JIRA and implementation of the application for synchronization defects from HP Quality Center to JIRA. The first part of the thesis defines the basic terminology of testing and testing principles. Second part contains description of the methodology TPI NEXT, focusing on its key areas. The next part of the thesis describes synchronization of HP Quality Center and JIRA in the context of testing process improvement. The main part of the thesis focuses on approaches to synchronization tools HP Quality Center and JIRA and specific implementation of synchronization bridge. This bridge allows unilateral synchronization of defects from HP Quality Center to JIRA and is written in Java.

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Panigrahi, Manaswita. "Energy and cost analysis of household electricity efficiency improvements in a rental apartment building." Thesis, Mittuniversitetet, Institutionen för teknik och hållbar utveckling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-17151.

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In this thesis potential for (final and primary) energy and CO2 emission reductions and cost effectiveness of replacing existing household electric appliances and light bulbs with most popular or most energy efficient appliances in a multifamily apartment building in Växjö city is studied. The results showed that there is significant potential to reduce electricity demand and thereby to reduce primary energy use and CO2 emissions. The greatest potential lies with replacing existing incandescent bulbs with LED bulbs, while the lowest savings seem to be with replacement of microwave ovens. Assuming that reduced electricity demand reduces electricity generation in coal-based steam turbine (CST) technology, annually about 63 MWh of primary energy and 25 ton CO2 emissions could be reduced from the investigated building if the existing refrigerator/freezer, stove/oven, microwave oven, televisions and light bulbs are replaced with the most energy efficient alternatives available in the market today. Also, the results from ‚discounted payback period‛ and ‚cost of conserved energy‛ analyses also showed that it is cost-effective to install the most energy efficient appliances. This study for a single building is based on limited number of interviews, selected appliance types, and number of assumptions about marginal electricity production systems. To generalize the results more such studies in different conditions with measurement of actual energy use of all the household appliances should be conducted, which would help to fully understand the potential of primary energy savings and CO2 emission reductions in Swedish apartment buildings.

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Souzy, Nicolas. "Experimental study and improvement of mass transfer in vertical bubble columns." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10201/document.

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Les colonnes à bulles sont utilisées en minéralurgie et en traitement des eaux pour capturer différents types de particules. Leur capacité d’échange bénéficie aujourd’hui d’un regain d’intérêt pour assurer la production de micro-algues destinées à un usage médicinal, alimentaire, ou énergétique : les concentrations d’oxygène et de dioxyde de carbone peuvent être contrôlées grâce à la considérable aire interfaciale gaz-liquide dans la colonne à bulles. Une étude expérimentale en boucle fermée a été menée pour simuler le passage du gaz dans une succession de colonnes en série. Le modèle théorique associé confirme le rôle critique du diamètre des bulles lors du transfert de masse. Un générateur de micro-bulles (MBG) innovant a été conçu et testé. Le prototype est capable de produire des micro-bulles d’un diamètre moyen Dbubble = 0.252 mm. L’invention a été officiellement déclarée. Le dernier chapitre a pour objet l’amélioration des méthodes de traitement de Fluorescence Induite par Plan Laser (PLIF), qui permettent d’obtenir les coefficients de transfert de masse kl. La première correction présentée prend en compte les variations de l’extinction de la fluorescence due au pH pendant la calibration et a été évaluée sur une mesure de concentration de CO2 dans le sillage d’une bulle en ascension libre dans une colonne d’eau. La seconde correction proposée doit être appliquée quand la distance de la région de mesure où les variations de pH sont observées augmente. La nécessité de cette correction a été illustrée par un cas test dans le sillage d’un nuage de bulles en ascension libre dans une colonne d’eau
Bubble column are involved in many industrial fields ranging from chemical industry to mineral processing. It recently became an industrial stake for the production of micro-algae intended for medicinal use, food or energy: the oxygen and carbon dioxide concentrations can be controlled via the efficient mass transfer induced by the significant gas-liquid interfaciale area into the bubble column. Firstly, experimental closed-loop study has been carried out to simulate the passage of gas in a succession of columns in series. The associated theoretical model confirms the critical importance of the bubble diameter for mass transfer.Therefore, an innovative Micro-Bubble Generator (MBG) has been designed and tested. The prototype is able to produce micro-bubbles of average diameter Dbubble = 0.252 mm. The invention has been officially declared. The last chapter aims at improving data treatment methods for Planar Laser-Induced Fluorescence (PLIF), which enables to obtain experimentally mass transfer coefficient kl through concentration measurements. The first presented correction takes into account variations of the fluorescence extinction due to pH during the calibration step, and has been evaluated on CO2 concentration measurement in the wake of a free rising bubble. The second proposed correction should be applied when the length in the measurement region over which pH variations are observed increases: variations of the extinction coefficient will affect the local incident light intensity and therefore the measurements. The need for this correction has been illustrated on a test case in the wake of a cloud of free rising bubbles

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Mancini, Ferdinando. "ENERGY EFFICIENCY IMPROVEMENTS OF HOUSEHOLD HEAT PUMP SYSTEMS." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3423220.

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Sustainable development is one of the major challenges that humanity faces today. The rational use of energy resources and the increase of systems efficiency seems to be an important task for all contexts of modern life, from industry to transport and household appliances. The interest on this subject is justified not only by the price of energy, which can potentially increase, but also by the need to reduce emissions of gases, which are thought to be responsible for global warming. This work wants to present innovative solutions for the energy efficiency improvement of household heat pump systems, with particular reference to heat pump dryers, domestic refrigerators and tap water heat pumps. Since clothes drying is a very energy-intensive process, in recent years much attention has been paid to the development of energy efficient dryers. The heat pump has been recognised as a very attractive technology for this application. Actual interest is focused on finding good alternatives to halocarbon refrigerants. Because it’s safe for domestic rooms, carbon dioxide is regarded as a possible substitute for the traditional synthetic compounds. In this research work, the CO2 transcritical cycle is compared with the traditional R134a subcritical cycle. The comparison is carried out with a theoretical analysis and experimental tests, returning a positive assessment for CO2 as working fluid. Tap water heat pumps are considered a privileged application for the employment of CO2 as refrigerant. This work presents an innovative upper cycle pressure control logic to face the optimisation problem, and also reports an experimental investigation of CO2 heat pump prototype, using a double wall plate heat exchanger gas cooler. This solution was studied as a possibility to reduce the risk of tap water contamination with lubricant oil. Here some innovative solutions for the energy efficiency improvements of household refrigerators are presented. An experimental study was carried out on a under-counter refrigerator to analyse the effect of the operating cycling frequency on the electric consumptions. The experimental results show a reduction in energy consumption when the frequency of the compressor start-up increases. To better understand these issues it was developed a dynamic simulation model for evaporators, based on the “moving boundary” scheme. Temporal integration of core variables makes the mean void fraction to be time-variant. The use of this kind of variables improves the model accuracy and speed, with respect to boundary variables, when the compressor start-up is simulated. This choice was considered suitable to simulate household refrigerators, which typically work with continuous on/off cycles. Finally it’s presented an innovative solution for the energy efficiency improvement of total no-frost combi refrigerators. In these systems the fresh food compartment is cooled by air streams coming from the freezer. Therefore, the refrigeration unit produces the cooling effect at a temperature which is suitable for the freezer, but considerably colder than what is needed for the fridge. Consequently the system works with the thermodynamic disadvantage of supplying the cooling power at the lowest level of temperature. It was studied a combined household refrigerator (fridge/freezer), which works with a single refrigeration unit, but with two different air-loops. The unit consists of a single evaporator, which is employed to cool both the compartments. The air flow, involving the heat exchanger, comes alternately from the fridge or from the freezer. In this way the system works at two different evaporating temperatures, improving the thermodynamic efficiency when the fresh food compartment requires the cooling supply.
Lo sviluppo sostenibile rappresenta una delle più importanti sfide che oggi l’umanità deve affrontare. L’uso razionale delle risorse energetiche e l’aumento dell’efficienza dei sistemi che le utilizzano, è un importante obiettivo per tutti i contesti della vita moderna, dal settore industriale, ai trasporti, agli elettrodomestici di uso quotidiano. L’interesse verso questo tema è giustificato, non solo dal prezzo dell’energia in potenziale aumento, ma anche dalla necessità di ridurre le emissioni dei gas che sono ritenuti responsabili del riscaldamento globale. Questo lavoro si inquadra nello studio di soluzioni tecnologiche innovative volte al miglioramento dell’efficienza energetica di apparecchiature domestiche, più precisamente macchine che operano con un ciclo inverso a compressione di vapore. In particolare verrà fatto riferimento ad asciugabiancheria a pompa di calore, refrigeratori domestici e pompe di calore per il riscaldamento di acqua calda sanitaria. Come è noto, le asciugatrici domestiche realizzano un processo termodinamico che richiede un elevato dispendio energetico. Per questo motivo negli ultimi anni si è dato molto spazio alla ricerca di soluzioni che ne possano ridurre i consumi elettrici, trovando nella tecnologia della pompa di calore una significativa possibilità di miglioramento. Oggi l’attenzione è rivolta a incrementarne ulteriormente l’efficienza energetica e a trovare dei sostituiti ai tradizionali fluidi refrigeranti alogenati per ridurne l’impatto sull’ambiente. Poiché non è né tossica né infiammabile, l’anidride carbonica è perfettamente compatibile con gli ambienti domestici, ed è vista come un possibile sostituto dei composti sintetici. In questo lavoro il ciclo transcritico ad anidride carbonica viene messo a confronto, sia su base teorica che sperimentale, con il ciclo subcritico a R134a. I risultati di questa indagine mostrano buone prospettive per l’impiego della CO2 in questa applicazione. Nella sezione successiva verranno approfonditi aspetti teorici e tecnologici delle pompe di calore dedicate al riscaldamento di acqua calda sanitaria, applicazione in cui il ciclo transcritico ad anidride carbonica risulta essere molto efficace. L’analisi prevede lo studio di logiche di controllo di tipo adattativo per l’ottimizzazione della pressione superiore di ciclo. Sarà inoltre presentato uno studio sperimentale di macchine operanti con gas-cooler a piastre a doppia parete, impiegato per ridurre il rischio di contaminazione del circuito idraulico. Verranno poi approfondite alcune tematiche legate al miglioramento dell’efficienza energetica dei refrigeratori domestici. Si riportano i risultati di un’indagine sperimentale condotta su un frigorifero domestico di tipo “sottotavolo”, i cui consumi elettrici sono stati monitorati al variare della frequenza ciclica di accensione del compressore. Per questa apparecchiatura è stata registrata una significativa riduzione dei consumi ad elevati frequenze. Per approfondire ulteriormente questi temi, mediante simulazione numerica, è stato sviluppato un modello per evaporatori in regime di funzionamento dinamico, seguendo uno schema di tipo “moving boundary”. Un’opportuna scelta delle variabili di stato (nello specifico, variabili corrispondenti a proprietà medie e non a grandezze di confine del modello) ha permesso di tenere conto delle variazioni nel tempo del grado di vuoto medio della zona bifase e di conseguire una maggiore velocità di simulazione dei transitori di avviamento del compressore. Questo modello è stato quindi sviluppato appositamente per la simulazione di refrigeratori domestici che operano in regime ciclico di funzionamento. Infine, nell’ottica del miglioramento dell’efficienza dei refrigeratori domestici combinati di tipo total-no-frost, viene presentata una soluzione innovativa per il ciclo termodinamico. In queste apparecchiature il vano dei prodotti freschi viene di solito raffreddato facendo circolare una piccola portata d’aria proveniente dal vano dei prodotti surgelati. Questo tipo di funzionamento è inefficiente, in quanto la potenza frigorifera viene erogata al più basso livello di temperatura. La soluzione studiata prevede, invece, di convogliare alternativamente verso l’evaporatore due flussi d’aria che raffreddano distintamente i due vani refrigerati. Così facendo è possibile differenziare due livelli di temperatura per la produzione della potenza frigorifera, conseguendo un aumento dell’efficienza energetica quando l’unità opera al raffreddamento del vano a temperatura positiva.

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Книги з теми "COP IMPROVEMENT"

Gupta, U. S. Crop improvement. Enfield, New Hampshire: Science Publishers, 1990.

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Crop improvement. Boulder: Westview Press, 1992.

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Diagnostic techniques for improving crop production. New York: Food Products Press, 1996.

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Wolf, Benjamin. Diagnostic techniques for improving crop production: Instructor's manual. New York: Food Products Press, 1996.

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1941-, Schoonhoven Aart van, Voysest O, and Centro Internacional de Agricultura Tropical., eds. Common beans: Research for crop improvement. Wallingford, Oxon, UK: C.A.B. International in association with Centro Internacional de Agricultura Tropical, 1991.

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Simmonds, N. W. Principles of crop improvement. Harlow, Essex, England: Longman Scientific & Technical, 1987.

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1943-, Dennis E. S., and Llewellyn D. J. 1954-, eds. Molecular approaches to crop improvement. Wien: Springer-Verlag, 1990.

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Mohan, Jain S., Brar D. S, and Ahloowalia B. S, eds. Molecular techniques in crop improvement. Dordrecht: Kluwer Academic Publishers, 2002.

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Murphy, Kevin, and Glafera Janet Matanguihan. Quinoa: Improvement and sustainable production. Hoboken, New Jersey: John Wiley & Sons, Inc., 2015.

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K, Jaiwal Pawan, and Singh Rana P, eds. Improvement strategies of leguminosae biotechnology. Boston, MA: Kluwer Academic Publishers, 2003.

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Ozyigit, Ibrahim Ilker, Ilhan Dogan, and Ebru Artam Tarhan. "Agrobacterium rhizogenes-Mediated Transformation and Its Biotechnological Applications in Crops." In Crop Improvement, 1–48. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_1.

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Rasheed, Awais, Tariq Mahmood, Alvina Gul-Kazi, and Abdul Mujeeb-Kazi. "An Overview of Omics for Wheat Grain Quality Improvement." In Crop Improvement, 307–44. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_10.

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Chandna, Ruby, and Khalid Rehman Hakeem. "From Agronomy to Molecular Genetics and Proteomics in an Effort to Improve Nitrogen Use Efficiency in Crops." In Crop Improvement, 345–62. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_11.

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Rasool, Saiema, Muneeb U. Rehman, Mohamed Mahgoub Azooz, Muhammad Iqbal, Tariq Omar Siddiqi, and Parvaiz Ahmad. "Arsenic Toxicity and Tolerance Mechanisms in Plants: An Overview." In Crop Improvement, 363–78. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_12.

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Sharma, Iti. "Arsenic Stress in Plants: An Inside Story." In Crop Improvement, 379–400. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_13.

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Siddiqui, Zahid Hameed, Abdul Mujib, Mahmooduzzafar, Junaid Aslam, Khalid Rehman Hakeem, and Talat Parween. "In vitro Production of Secondary Metabolites Using Elicitor in Catharanthus roseus: A Case Study." In Crop Improvement, 401–19. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_14.

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Miransari, Mohammad. "Handling Soybean (Glycine max L.) Under Stress." In Crop Improvement, 421–39. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_15.

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Benzarti, Maali, Kilani Ben Rejeb, Ahmed Debez, and Chedly Abdelly. "Environmental and Economical Opportunities for the Valorisation of the Genus Atriplex: New Insights." In Crop Improvement, 441–57. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_16.

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Wimalasekara, Rinukshi, and Günther F. E. Scherer. "Dealing with Environmental Stresses: Role of Polyamines in Stress Responses." In Crop Improvement, 459–83. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_17.

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De Filippis, L. F. "Bioinformatic Tools in Crop Improvement." In Crop Improvement, 49–122. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-7028-1_2.

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Тези доповідей конференцій з теми "COP IMPROVEMENT"

Garimella, Srinivas. "Absorption Heat Pump Performance Improvement Through Ground Coupling." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1005.

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Abstract The present study investigates the improvement in the performance of an absorption heat pump for residential space-conditioning due to the use of the ground as the heat source in the heating mode and the heat sink in the cooling mode. A baseline air-coupled single-effect ammonia-water heat pump is first designed to deliver 10.55 kW (36,000 Btu/hr) of cooling load at the ARI rating conditions. Particular attention is paid to incorporating many realistic details of an operating system such as fuel combustion efficiencies of the burner, non-equilibrium conditions, and moist air processes in the air-coupled heat exchangers. A range of parametric studies is also conducted to investigate the variation in performance of this system with ambient conditions in the heating and cooling modes. The same system is then analyzed in a ground-coupled configuration. The instantaneous COP for the ground-coupled system is compared with the COP of the air-coupled system as a function of the time of the year and the corresponding variations in ambient and ground temperatures using thirty-year average climate data for various locations from the National Weather Service. Improvements in COP of up to twenty percent over the air-coupled system values (cooling mode COP of 0.495 at 35°C (95°F) and heating mode COP of 1.20 at 8.33°C (47°F)) are demonstrated in diverse geographic locations with widely varying heating and cooling loads. These improvements indicate that an efficient ground-coupled heat pump could be developed for residential space-conditioning applications using simple thermodynamic cycles and existing technology for the heat and mass exchange components.

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Hwang, Yunho, Hans-Joachim Huff, Marcus Preissner, and Reinhard Radermacher. "CO2 Transcritical Cycles for High Temperature Applications." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/aes-23630.

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Abstract A breadboard CO2 prototype heat pump for stationary applications was designed, constructed, and tested. Test results of the CO2 prototype showed about 12% lower cooling capacity but a similar cooling Coefficient of Performance (COP) at 40°C (104°F) ambient temperature as compared to R-22 environmental control units (ECU). However the projected COP of the CO2 prototype at 52°C (125°F) is lower than that of the original R-22 ECU. Therefore it is necessary to investigate methods to improve the efficiency while considering the design issues especially for high temperature operation. As means to improve the performance of the CO2 cycle at higher ambient conditions, four methods were investigated: a suction-line heat exchanger, an expander, an evaporatively cooled gas cooler, and a two-stage split cycle. It is expected that a suction-line heat exchanger can increase the high temperature capacity and COP of a CO2 system by approximately 10% and 20%, respectively. For an expander inlet temperature of 52 °C (125°F), the COP improvement is about 27% with an expander efficiency of 50%. An improvement in COP of 17% to 24% is achieved by using an evaporatively cooled gas cooler while the system cooling capacity improved by 6% to 8% at ambient temperatures of 35°C (95°F) and 45°C (113°F), respectively. The two-stage split cycle with intercooling offers 38% to 63% COP improvement at 30 to 50°C (86 to 122°F) ambient conditions. If one of these methods are implemented, the performance of the CO2 system can compete with R-22 ECUs. If two or more of above methods are implemented, the benefits may be higher than each one of them. However the benefit cannot be simply superpositioned due to the counteract effects. Therefore, the benefits of the implementation of two or more of above methods remain as a further study.

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Ilis, Gamze Gediz. "COP IMPROVEMENT OF ELECTRIC VEHICLE BATTERY THERMAL MANAGEMENT SYSTEM WITH AN ADSORPTION HEAT PUMP." In Second Thermal and Fluids Engineering Conference. Connecticut: Begellhouse, 2017. http://dx.doi.org/10.1615/tfec2017.ist.018033.

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Qian, Suxin, Abdullah Alabdulkarem, Jiazhen Ling, Yunho Hwang, and Reinhard Radermacher. "Study on Performance Improvement of a Compressive Thermoelastic Cooling System Using Single Objective Optimization." In ASME 2015 9th International Conference on Energy Sustainability collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/es2015-49745.

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Thermoelastic cooling, also known as elastocaloric cooling, is one alternative cooling technology aiming to reduce the use of global warming potential refrigerants in vapor compression cycles. The cooling is based on the latent heat associated with the martensitic phase change induced by stress in shape memory alloys, driven by either compression or tension. A few past studies have explored and proposed the cycle options and system setup of a compressive thermoelastic cooling system using nitinol tubes as working material. The system coefficient of performance (COP) and cooling capacity were predicted by a dynamic model based on the physics of the integrated complicated heat transfer process and martensitic phase change. This study aims to start the performance improvement studies via optimization using the model. The objective function of the optimization problem is COP. Design variables include a few important operating parameters, such as flow rates and cycle frequency. The previously developed dynamic model is used to evaluate the system performance for this study. It is estimated that the COP enhancement can be as large as 51% from the baseline design candidate. Finally, an updated performance improvement potential is presented to guide future studies.

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Sajjad, Saqib, and Haseeb Ali. "Energy Performance Benchmarking of Process Refrigeration Units." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207404-ms.

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Abstract Process refrigeration units are one of the major energy consumers at gas processing plants. Owing to the higher energy consumption, evaluation and benchmarking of energy performance of the refrigeration units is very important for identification of energy saving opportunities. In this regard, an energy performance benchmarking study was performed by detailed assessment and evaluation of the existing process refrigeration units to identify potential of energy efficiency improvement. The study encompassed twenty-one (21) process refrigeration units installed at five (05) different sites. The methodology included collection and analysis of design & operation data and review of key variables like percent load, anti-surge valve opening, condensing temperature & pressure and chilling temperature etc. Energy Performance Indicators (EnPIs) considered for the benchmarking were compressor's specific energy, coefficient of performance (COP) and relative COP (RCOP). A thermodynamic model was developed for each unit to ascertain the refrigeration load. Instead of usual high level benchmarking techniques, the study considered unit and equipment level benchmarking which provided better insight of the systems and helped in finding opportunities for energy efficiency improvement. Further, COP which is generally considered as a benchmarking EnPI, only considers refrigeration load and energy consumption, whereas, this study introduced a new EnPI named "Relative COP" which additionally takes into account the chilling and condensing temperatures and gives true energy performance benchmarking.

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Shehadi, Maher. "Experimental and Analytical Study for Condenser Shading Effects on Air-Conditioning System Performance." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23215.

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Abstract An experimental and analytical study for performance of shaded condensers is presented. A three tons of refrigeration (TR) unit installed in a 2-story house was experimentally studied between June and September. Analytical simulations for a 3 TR unit and for a wider range of capacities ranging from 80 to 370 TR was done. The experimental results for the 3 TR unit showed 12–39% improvement in the COP of the cycle under various evaporator temperatures with uncertainty levels between ±1.63–13.6%. The simulated results for the same capacity (3 TR) showed higher improvements than the experimental ones. However, for larger capacities, the simulations showed lower improvements than the 3 TR unit and ranged between 10–14%.

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Takeshita, Keisuke, Yoshiharu Amano, and Takumi Hashizume. "Demonstration of a Hybrid Power and Refrigeration Ammonia-Water Cycle." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91319.

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This paper reports on the demonstration of a hybrid power generation and refrigeration cycle in a turbine system which employs ammonia-water mixture as the working fluid. The hybrid cycle is the one in which the ammonia-water mixture turbine cycle and the ammonia absorption refrigerator are combined. To demonstrate the performance enhancement of the hybrid cycle, its steady state characteristics were experimentally investigated. The increase of the coefficient of performance (COP) and the performance improvement of the cycle are mainly due to a reduction of the heat of rectification at the ammonia absorption refrigerator. Therefore, the authors especially focused on the COP, the heat source steam consumption rate, and the heat of rectification when the ammonia mass fraction at the rectifier inlet increased. Results showed the COP and heat source steam consumption rate improved about 20% in hybrid operation, compared with normal operation which drives the ammonia absorption refrigerator and the ammonia-water mixture turbine cycle separately.

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Ludovisi, Daniele, William M. Worek, and Milton Meckler. "VRA Enhancement of Two Stage LiBr Chiller Performance Improves Sustainability." In ASME 2007 Energy Sustainability Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/es2007-36109.

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Multi-effect LiBr absorption chiller must take advantage of higher temperature heat sources to achieve higher COP so as to be competitive with lower first cost comparable commercially available, efficient electric chillers under current market pricing conditions. Yet a nominal conventional double-effect absorption chiller operating at a COP of 1.0 versus a comparable efficient motor driven centrifugal chiller operating at a COP of 7.0 will consume slightly less than twice the amount of prime natural gas (NG) source energy assuming a local 28% NG fired electric utility plant’s annual average efficiency and a 10% gas distribution leakage and 10% electric transmission loss to user’s meter. However if the COP of the above referenced double-effect LiBr absorption chiller were doubled, it would consume approximately the same amount of prime NG source energy and equally sustainable from an environmental impact standpoint. Consequently research to further improve double-effect LiBr absorption chillers beyond the VRA benefits reported to date was investigated in this study. Former simulation studies of a low differential pressure-vapor recompression absorber (VRA) reported in 2001 indicated a 7% COP efficiency gain, while additional simulation studies reported in 2006 indicated a 38% COP efficiency gain with the VRA operating at elevated differential pressures at the same upper stage concentrator temperature previously considered. Double-effect LiBr absorption chillers are limited by corrosion effects, which have been shown to accelerate significantly above 160 °C. In this paper, a reverse series flow, double-effect LiBr absorption chiller employing a VRA is investigated over a wider range of upper stage concentrator and absorber cooling temperatures but operating at the same low and elevated pressure differential levels reported earlier showed significant improvement in COP efficiency, capacity performance and projected hybrid operational cost.

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Khan, Muhammad Saad, Sambhaji T. Kadam, Alexios-Spyridon Kyriakides, Ibrahim Hassan, Athanasios I. Papadopoulos, Mohammad Azizur Rahman, and Panos Seferlis. "Modified Operating Parameter-Based Iyer Correlation for the Coefficient of Performance (COP) Prediction of Different Fluid Pairs in Double-Effect Vapor Absorption Refrigeration (VAR) Cycles." In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65709.

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Abstract Vapor absorption refrigeration (VAR) is a sustainable alternative to the conventional vapor compression refrigeration (VCR) cycle, owing to its lower non-renewable energy requirements and potentially for exploitation of renewable energy sources. Traditionally, the coefficient of performance (COP) of the conventional single effect VAR cycle is considerably lower than VCR cycles. This provides room for improvement which can be attained through double effect VAR cycles that provide relatively higher performance. The COP of the dual effect VAR cycle is enhanced due to the waste/rejected heat energy utilization from the condenser or the absorber into a secondary generator. Models that correlate the COP of the double effect VAR cycle with operating parameters are not available in the open literature, with Iyer’s correlation being the only exception. This work applies this COP correlation using literature data for double effect VAR that operate with a variety of refrigerant and absorbent pairs. A comprehensive Mean Absolute Percentage Error (MAPE) analysis is performed for more than 2028 data points of various fluid pairs. Results reveal that MAPE (86.6–839%) values appear to be quite high for the reported correlation. Furthermore, the model is optimized using the proposed data set, considerably reducing the MAPE up to 36.03%. The results also indicate that due to the lack of fluid-specific parameters, the application of this correlation may not support the development of new double effect VAR cycles. Therefore, it is crucial to establish a performance-based correlation that considers both operational parameters and fluid parameters to assess the performance of new and efficient dual effect VAR cycles.

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Huynh, Dan, J. Josiah Steckenrider, and Gregory Freisinger. "Probabilistic Estimation of Posture Metrics Using Novel Loadsols." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-69409.

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Abstract This paper presents an original technique for estimating human posture metrics using Novel Loadsols®. Under the proposed technique, center of pressure (COP) metrics are derived by combining physics- and data-driven estimates to achieve reasonably high accuracy at relatively low cost. To develop a training set upon which the probabilistic data model was constructed, 79 trials were conducted in which participants stood comfortably still for 30 seconds at a time simultaneously on a force plate and a pair of Loadsols, where the force plate is considered to be the gold-standard of COP measurement. These data were then used to generate Gaussian mixture models (GMMs) of pairwise combinations of force plate and Loadsol metrics. The GMMs can then be conditioned on Loadsol measurements and fused using Bayesian inference. When the training set was re-processed by converting 12 Loadsol metrics into estimated force plate metrics, it was found that the converted metrics matched ground-truth more accurately on average than raw Loadsol metrics. Furthermore, there was improvement in the r2 values of the regression lines after conversion for 75% of the metrics. Given some experiment and algorithm refinement, the proposed probabilistic approach has potential to offer the accuracy of force plate COP estimation at a fraction of the cost.

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Звіти організацій з теми "COP IMPROVEMENT"

Morrow, III, William R., Ali Hasanbeigi, and Tengfang Xu. Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Cement Industry. Office of Scientific and Technical Information (OSTI), December 2012. http://dx.doi.org/10.2172/1172247.

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David S. Schechter. Investigation of Efficiency Improvements During CO2 Injection in Hydraulically and Naturally Fractured Reservoirs. Office of Scientific and Technical Information (OSTI), December 2005. http://dx.doi.org/10.2172/897541.

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David S. Schechter. INVESTIGATION OF EFFICIENCY IMPROVEMENTS DURING CO2 INJECTION IN HYDRAULICALLY AND NATURALLY FRACTURED RESERVOIRS. Office of Scientific and Technical Information (OSTI), September 2005. http://dx.doi.org/10.2172/885159.

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Schechter, David S., and Harold Vance. Investigation of Efficiency Improvements During CO2 Injection in Hydraulically and Naturally Fractured Reservoirs. Office of Scientific and Technical Information (OSTI), March 2003. http://dx.doi.org/10.2172/808646.

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